Tre, Pol, Pen.
“By their Tre, their Pol, and Pen,
Ye shall know the Cornish men.”
“By their Tre, their Pol, and Pen,
Ye shall know the Cornish men.”
Entry taken from Dictionary of Phrase and Fable, edited by the Rev. E. Cobham Brewer, LL.D. and revised in 1895.